Enhanced wear resistance of Ti reinforced Inconel 718 superalloy manufactured by laser directed energy deposition

Abstract

Laser directed energy deposition method has been widely employed in manufacturing nickel based superalloy components of gas turbines and aero engines. However, the laser deposited superalloy presents low wear resistance, implying a serious wear during long time service. Here, the microstructure and wear behavior of Ti reinforced Inconel 718 superalloy are investigated for alloys manufactured by laser directed energy deposition technology. Results discovered that amounts of Laves phases are decreased when the fraction of added Ti increases from 0 to 5 wt%. Meanwhile, amounts of δ phase are increased. For the fraction of strengthening phases, γ'′ phases' fraction is reduced, while the fraction of γ' phases is increased continuously. Majority of the grains in deposited alloys grow along the [001] crystallographic direction. The best wear resistance is exhibited in the deposited alloy with 5 wt% Ti added for the smallest wear rate. While, the largest wear rate for the as-received alloy implies the worst wear resistance. An increasing wear resistance is exhibited for the decreased wear rates under the increased fraction of added Ti. The dominant wear mechanism in the deposited Inconel 718 superalloy is detected to be abrasive wear, and it is greatly affected by the fraction of the strengthening phases. The further understanding of the wear behavior presents an effective method for strengthening deposited superalloy components that are employed in complicated working environments.